You can find conflicting ports with the lsof command. Use lsof -i :143 for instance to find what
is using imap port 143. If you find a conflict, then you just have to eliminate the conflict.
This error was caused on my system by the presence of the rpc.stated daemon. To disable
simply run chkconfig nfslock off and restart your system. Strangely, when I dovecot started
normally, you could then start the rpc.stated daemon without conflict. I left it disabled however
as I didn’t need it on that system.
Another handy utility for a Centos system is ntsysv. This gives you a gui view of daemons on
your system and the ability to turn them on or off.